1. Field of the Invention
This invention relates to a display device provided with a protecting cover, and particularly to a display device which is preferably applied to a liquid crystal display device.
2. Description of the Related Art
In an outdoor setting-up display device using liquid crystal, in many cases, in order to protect the display panel from outside shock or flooding due to rainfall, the display plane of a display panel is covered with a transparent protecting cover made of resin or glass and is subjected to waterproofing at the periphery thereof.
Where the protecting cover is arranged on the display plane of the display panel, since an air layer exists between the display panel and protecting cover, a problem occurs that outside light incident on the display plane reflects from the front and back sides of the transparent protecting cover and the surface of a flat panel, thereby to deteriorate visibility.
In order to solve such a problem, some techniques were proposed in which the gap between the display panel and protecting cover is filled with transparent resin, or a light permeable adhesive sheet is arranged in the gap (for example, see JP-A-2006-290960).
In the technique in which the gap between the display panel and the protecting cover is filled with the liquid transparent resin, the resin invades the inside of the display panel from the gap between the frame holding the display panel and the display panel, thereby providing a problem of making the resin invaded inside visible. In order to solve this problem, it was necessary to form a sealing member for suppressing invasion of the resin between the frame and the display panel, thereby increasing the working number of man-hours.
Further, in the technique in which the transparent adhesive sheet is arranged in the gap between the display panel and protecting cover so that the protecting cover is affixed to the display panel, a level difference is generated between the frame arranged so as to cover the periphery edge of the display plane of the display panel and the display plane of the display panel. For this reason, in affixing the protecting cover using the transparent adhesive sheet, air bubbles get mixed in the vicinity of the level difference, thereby remarkably deteriorating the display quality. In order to suppress the air bubbles, it is necessary to arrange the transparent adhesive sheet on only the display plane of the display device. However, in this configuration, the frame, display panel and protecting cover cannot be secured, thereby giving a problem of reducing the shocking strength of the display device.